Almost all Fecker scopes use the central focus adjustment, and no other maker used that. Surprised the mounts don't have Fecker stamped into them? I own quite a few Fecker scopes as they're my favorite because of the center adjustment. But a couple years ago at the CGCS Greeley show I found my first Fecker without center focus! So far I've been unable to find anyone with vintage scope knowledge whose ever seen a Fecker like it.